public class Example3_6 {
   public static void main(String args[]) {
     double sum = 0,item = 1;
     int i = 1,n = 20;
     while(i<=n) {
        sum = sum+item;
        i = i+1;
        item = item*(1.0/i);
     }
     System.out.println("sum="+sum);
   }
}
